# Telnyx Calling: Voice API — Documentation Index
> Voice API documentation within the Calling section of the Telnyx developer docs (https://developers.telnyx.com).
> Root index: https://developers.telnyx.com/llms.txt · Calling index: https://telnyx.com/llms/calling.txt · Full content for this subsection: https://telnyx.com/llms/calling/voice-api-full.txt

## Voice API Fundamentals

- [Getting Started](https://developers.telnyx.com/docs/voice/programmable-voice/voice-api-fundamentals.md): Complete step-by-step guide to get started with Telnyx Voice API, from account creation to making your first call.
- [Commands and Resources](https://developers.telnyx.com/docs/voice/programmable-voice/voice-api-commands-and-resources.md): Reference of Telnyx Voice API commands and resources — calls, conferences, recordings, transcriptions — with usage patterns and lifecycle examples.
- [Webhooks](https://developers.telnyx.com/docs/voice/programmable-voice/voice-api-webhooks.md): Reference for Voice API webhook events, payloads, configuration, and delivery behavior.
- [Sending Commands](https://developers.telnyx.com/docs/voice/programmable-voice/sending-commands.md): Send voice commands to Telnyx Programmable Voice — answer, hangup, transfer, play audio, gather DTMF — with code examples and parameter reference.
- [Receiving Webhooks](https://developers.telnyx.com/docs/voice/programmable-voice/receiving-webhooks.md): Receive Telnyx Programmable Voice webhooks to drive call flow in real time. Includes event types, payload structure, retries, and SDK examples.
- [Command Retries](https://developers.telnyx.com/docs/voice/programmable-voice/command-retries.md): Telnyx's Programmable Voice Resources page explain in detail how to

## Voice Features

- [Speech-to-Text](https://developers.telnyx.com/docs/voice/programmable-voice/speech-to-text.md): Transcribe Telnyx Programmable Voice calls with the Voice API and TeXML. Includes language selection, real-time vs post-call modes, and code samples.
- [Text-to-Speech](https://developers.telnyx.com/docs/voice/programmable-voice/tts.md): Use text-to-speech on Telnyx Programmable Voice to speak prompts and dynamic content. Supports AWS Polly, Google, ElevenLabs, Azure, and Telnyx voices.
- [Call Queueing](https://developers.telnyx.com/docs/voice/programmable-voice/queueing-calls.md): how to use the Telnyx Call Queue API to create and manage call
- [Answering Machine Detection](https://developers.telnyx.com/docs/voice/programmable-voice/answering-machine-detection.md): Telnyx's Programmable Voice lets you build custom answering machine
- [Call Recordings Storage](https://developers.telnyx.com/docs/voice/programmable-voice/storing-call-recordings.md): Telnyx's Programmable Voice gives customers the ability to store
- [SIPREC Server Configuration](https://developers.telnyx.com/docs/voice/programmable-voice/siprec-server.md): Configure a Telnyx SIPREC session recording server (SRS) to capture and store VoIP call media for compliance, quality assurance, and call archival.
- [SIPREC Client](https://developers.telnyx.com/docs/voice/programmable-voice/siprec-client.md): Use the Telnyx SIPREC client to record Voice API and TeXML calls to an external SIPREC server. Includes session setup, metadata, and security options.

## AI Capabilities

- [SSML Tags](https://developers.telnyx.com/docs/voice/programmable-voice/ssml-tags.md): Programmable voice with SSML tags from Telnyx - perfect for your
- [Gather Using AI](https://developers.telnyx.com/docs/voice/programmable-voice/gather-using-ai.md): Capture caller input with AI on Telnyx Programmable Voice. Use Gather using AI to transcribe speech, classify intent, and branch your IVR dynamically.
- [Attach an AI Assistant to a Call](https://developers.telnyx.com/docs/voice/programmable-voice/ai-assistant-start.md): Learn how to attach a pre-configured AI assistant to a live call using the ai_assistant_start command.
- [Dialogflow Integration](https://developers.telnyx.com/docs/voice/programmable-voice/dialogflow-es.md): Telnyx's Dialogflow tutorial will teach you how to create and
- [Real-Time Media Streaming](https://developers.telnyx.com/docs/voice/programmable-voice/media-streaming.md): Stream call audio in real time over WebSockets with Telnyx Programmable Voice for transcription, AI integration, and bidirectional media.
- [Conversation Relay](https://developers.telnyx.com/docs/voice/programmable-voice/conversation-relay.md): Use Conversation Relay to connect Telnyx calls to your WebSocket application for real-time speech, DTMF, and text-to-speech control.
- [Noise Suppression](https://developers.telnyx.com/docs/voice/programmable-voice/noise-suppression.md): Enable AI noise suppression on Telnyx Programmable Voice calls to remove background noise from inbound and outbound audio for clearer conversations.
- [Deepfake Detection](https://developers.telnyx.com/docs/voice/programmable-voice/deepfake-detection.md): Detect AI-generated voices on live calls with Telnyx's real-time

## Tutorials

- [IVR](https://developers.telnyx.com/docs/voice/programmable-voice/ivr-demo.md): How to build an IVR using Telnyx Voice API. Start building on Telnyx today.
- [Call Center](https://developers.telnyx.com/docs/voice/programmable-voice/call-center.md): How to build a call center application using Telnyx APIs. Start
- [Call Tracking](https://developers.telnyx.com/docs/voice/programmable-voice/call-tracking.md): How to build a call tracking application using Telnyx Voice API.
- [Conferencing](https://developers.telnyx.com/docs/voice/programmable-voice/conferencing-demo.md): How to build a conferencing using Telnyx Voice API. Start building

## Regional & Restrictions

- [Voice API Services in Europe](https://developers.telnyx.com/docs/voice/programmable-voice/voice-api-services-in-europe.md): Telnyx Voice API services in Europe — use European points of presence to reduce latency and meet data residency requirements for EU-based voice apps.
- [L1 Account Restrictions](https://developers.telnyx.com/docs/voice/programmable-voice/l1-accounts-restirctions.md): Restrictions that apply to Programmable Voice on Telnyx L1 verified accounts — automated speak warnings, call limits, and steps to upgrade verification.

## API Reference (Voice API)

### Call Control Applications

- [List call control applications](https://developers.telnyx.com/api-reference/call-control-applications/list-call-control-applications.md): Return a list of call control applications.
- [Create a call control application](https://developers.telnyx.com/api-reference/call-control-applications/create-a-call-control-application.md): Create a call control application.
- [Retrieve a call control application](https://developers.telnyx.com/api-reference/call-control-applications/retrieve-a-call-control-application.md): Retrieves the details of an existing call control application.
- [Update a call control application](https://developers.telnyx.com/api-reference/call-control-applications/update-a-call-control-application.md): Updates settings of an existing call control application.
- [Delete a call control application](https://developers.telnyx.com/api-reference/call-control-applications/delete-a-call-control-application.md): Deletes a call control application.

### Call Information

- [List all active calls for given connection](https://developers.telnyx.com/api-reference/call-information/list-all-active-calls-for-given-connection.md): Lists all active calls for given connection. Acceptable connections are either SIP connections with webhook_url or xml_request_url, call control or texml. Retu…
- [Retrieve a call status](https://developers.telnyx.com/api-reference/call-information/retrieve-a-call-status.md): Returns the status of a call (data is available 10 minutes after call ended).

### Debugging

- [List call events](https://developers.telnyx.com/api-reference/debugging/list-call-events.md): Filters call events by given filter parameters. Events are ordered by `occurred_at`. If filter for `leg_id` or `application_session_id` is not present, it only…

### Call Commands

- [Dial](https://developers.telnyx.com/api-reference/call-commands/dial.md): Dial a number or SIP URI from a given connection. A successful response will include a `call_leg_id` which can be used to correlate the command with subsequent…
- [Answer call](https://developers.telnyx.com/api-reference/call-commands/answer-call.md): Answer an incoming call. You must issue this command before executing subsequent commands on an incoming call.
- [Bridge calls](https://developers.telnyx.com/api-reference/call-commands/bridge-calls.md): Bridge two call control calls.
- [Start AI Assistant](https://developers.telnyx.com/api-reference/call-commands/start-ai-assistant.md): Start an AI assistant on the call.
- [Join AI Assistant Conversation](https://developers.telnyx.com/api-reference/call-commands/join-ai-assistant-conversation.md): Add a participant to an existing AI assistant conversation. Use this command to bring an additional call leg into a running AI conversation.
- [Stop AI Assistant](https://developers.telnyx.com/api-reference/call-commands/stop-ai-assistant.md): Stop an AI assistant on the call.
- [Add messages to AI Assistant](https://developers.telnyx.com/api-reference/call-commands/add-messages-to-ai-assistant.md): Add messages to the conversation started by an AI assistant on the call.
- [Start Conversation Relay](https://developers.telnyx.com/api-reference/call-commands/start-conversation-relay.md): Start a Conversation Relay session on an active call. Conversation Relay connects the call audio to your WebSocket so your application can exchange realtime me…
- [Stop Conversation Relay](https://developers.telnyx.com/api-reference/call-commands/stop-conversation-relay.md): Stop the active Conversation Relay session on a call.
- [Update client state](https://developers.telnyx.com/api-reference/call-commands/update-client-state.md): Updates client state
- [Enqueue call](https://developers.telnyx.com/api-reference/call-commands/enqueue-call.md): Put the call in a queue.
- [Forking start](https://developers.telnyx.com/api-reference/call-commands/forking-start.md): Call forking allows you to stream the media from a call to a specific target in realtime.
- [Forking stop](https://developers.telnyx.com/api-reference/call-commands/forking-stop.md): Stop forking a call.
- [Gather](https://developers.telnyx.com/api-reference/call-commands/gather.md): Gather DTMF signals to build interactive menus.
- [Gather stop](https://developers.telnyx.com/api-reference/call-commands/gather-stop.md): Stop current gather.
- [Gather using AI](https://developers.telnyx.com/api-reference/call-commands/gather-using-ai.md): Gather parameters defined in the request payload using a voice assistant.
- [Gather using audio](https://developers.telnyx.com/api-reference/call-commands/gather-using-audio.md): Play an audio file on the call until the required DTMF signals are gathered to build interactive menus.
- [Gather using speak](https://developers.telnyx.com/api-reference/call-commands/gather-using-speak.md): Convert text to speech and play it on the call until the required DTMF signals are gathered to build interactive menus.
- [Hangup call](https://developers.telnyx.com/api-reference/call-commands/hangup-call.md): Hang up the call.
- [Reject a call](https://developers.telnyx.com/api-reference/call-commands/reject-a-call.md): Reject an incoming call.
- [Remove call from a queue](https://developers.telnyx.com/api-reference/call-commands/remove-call-from-a-queue.md): Removes the call from a queue.
- [Play audio URL](https://developers.telnyx.com/api-reference/call-commands/play-audio-url.md): Play an audio file on the call. If multiple play audio commands are issued consecutively,
- [Stop audio playback](https://developers.telnyx.com/api-reference/call-commands/stop-audio-playback.md): Stop audio being played on the call.
- [Recording start](https://developers.telnyx.com/api-reference/call-commands/recording-start.md): Start recording the call. Recording will stop on call hang-up, or can be initiated via the Stop Recording command.
- [Recording stop](https://developers.telnyx.com/api-reference/call-commands/recording-stop.md): Stop recording the call.
- [Record resume](https://developers.telnyx.com/api-reference/call-commands/record-resume.md): Resume recording the call.
- [Record pause](https://developers.telnyx.com/api-reference/call-commands/record-pause.md): Pause recording the call. Recording can be resumed via Resume recording command.
- [Send DTMF](https://developers.telnyx.com/api-reference/call-commands/send-dtmf.md): Sends DTMF tones from this leg. DTMF tones will be heard by the other end of the call.
- [SIP Refer a call](https://developers.telnyx.com/api-reference/call-commands/sip-refer-a-call.md): Initiate a SIP Refer on a Call Control call. You can initiate a SIP Refer at any point in the duration of a call.
- [SIPREC start](https://developers.telnyx.com/api-reference/call-commands/siprec-start.md): Start siprec session to configured in SIPREC connector SRS.
- [SIPREC stop](https://developers.telnyx.com/api-reference/call-commands/siprec-stop.md): Stop SIPREC session.
- [Speak text](https://developers.telnyx.com/api-reference/call-commands/speak-text.md): Convert text to speech and play it back on the call. If multiple speak text commands are issued consecutively, the audio files will be placed in a queue awaiti…
- [Streaming start](https://developers.telnyx.com/api-reference/call-commands/streaming-start.md): Start streaming the media from a call to a specific WebSocket address or Dialogflow connection in near-realtime. Audio will be delivered as base64-encoded RTP…
- [Streaming stop](https://developers.telnyx.com/api-reference/call-commands/streaming-stop.md): Stop streaming a call to a WebSocket.
- [Noise Suppression Start (BETA)](https://developers.telnyx.com/api-reference/call-commands/noise-suppression-start-beta.md)
- [Noise Suppression Stop (BETA)](https://developers.telnyx.com/api-reference/call-commands/noise-suppression-stop-beta.md)
- [Switch supervisor role](https://developers.telnyx.com/api-reference/call-commands/switch-supervisor-role.md): Switch the supervisor role for a bridged call. This allows switching between different supervisor modes during an active call
- [Transcription start](https://developers.telnyx.com/api-reference/call-commands/transcription-start.md): Start real-time transcription. Transcription will stop on call hang-up, or can be initiated via the Transcription stop command.
- [Transcription stop](https://developers.telnyx.com/api-reference/call-commands/transcription-stop.md): Stop real-time transcription.
- [Transfer call](https://developers.telnyx.com/api-reference/call-commands/transfer-call.md): Transfer a call to a new destination. If the transfer is unsuccessful, a `call.hangup` webhook for the other call (Leg B) will be sent indicating that the tran…

### Callbacks

- [Call Initiated](https://developers.telnyx.com/api-reference/callbacks/call-initiated.md)
- [Call Answered](https://developers.telnyx.com/api-reference/callbacks/call-answered.md)
- [Call Streaming Started](https://developers.telnyx.com/api-reference/callbacks/call-streaming-started.md)
- [Call Streaming Stopped](https://developers.telnyx.com/api-reference/callbacks/call-streaming-stopped.md)
- [Call Streaming Failed](https://developers.telnyx.com/api-reference/callbacks/call-streaming-failed.md)
- [Call Deepfake Detection Result](https://developers.telnyx.com/api-reference/callbacks/call-deepfake-detection-result.md)
- [Call Deepfake Detection Error](https://developers.telnyx.com/api-reference/callbacks/call-deepfake-detection-error.md)
- [Call Bridged](https://developers.telnyx.com/api-reference/callbacks/call-bridged.md)
- [Call Conversation Ended](https://developers.telnyx.com/api-reference/callbacks/call-conversation-ended.md)
- [Call Conversation Insights Generated](https://developers.telnyx.com/api-reference/callbacks/call-conversation-insights-generated.md)
- [Call Enqueued](https://developers.telnyx.com/api-reference/callbacks/call-enqueued.md)
- [Call Left Queue](https://developers.telnyx.com/api-reference/callbacks/call-left-queue.md)
- [Call Fork Started](https://developers.telnyx.com/api-reference/callbacks/call-fork-started.md)
- [Call Fork Stopped](https://developers.telnyx.com/api-reference/callbacks/call-fork-stopped.md)
- [Call Gather Ended](https://developers.telnyx.com/api-reference/callbacks/call-gather-ended.md)
- [Call Dtmf Received](https://developers.telnyx.com/api-reference/callbacks/call-dtmf-received.md)
- [Call AI Gather Ended](https://developers.telnyx.com/api-reference/callbacks/call-ai-gather-ended.md)
- [Call AI Gather Message History Updated](https://developers.telnyx.com/api-reference/callbacks/call-ai-gather-message-history-updated.md)
- [Call AI Gather Partial Results](https://developers.telnyx.com/api-reference/callbacks/call-ai-gather-partial-results.md)
- [Call Playback Started](https://developers.telnyx.com/api-reference/callbacks/call-playback-started.md)
- [Call Playback Ended](https://developers.telnyx.com/api-reference/callbacks/call-playback-ended.md)
- [Call Hangup](https://developers.telnyx.com/api-reference/callbacks/call-hangup.md)
- [Call Recording Saved](https://developers.telnyx.com/api-reference/callbacks/call-recording-saved.md)
- [Call Speak Ended](https://developers.telnyx.com/api-reference/callbacks/call-speak-ended.md)
- [Call Recording Error](https://developers.telnyx.com/api-reference/callbacks/call-recording-error.md)
- [Call Recording Transcription Saved](https://developers.telnyx.com/api-reference/callbacks/call-recording-transcription-saved.md)
- [Call Refer Started](https://developers.telnyx.com/api-reference/callbacks/call-refer-started.md)
- [Call Refer Completed](https://developers.telnyx.com/api-reference/callbacks/call-refer-completed.md)
- [Call Refer Failed](https://developers.telnyx.com/api-reference/callbacks/call-refer-failed.md)
- [Call Siprec Started](https://developers.telnyx.com/api-reference/callbacks/call-siprec-started.md)
- [Call Siprec Stopped](https://developers.telnyx.com/api-reference/callbacks/call-siprec-stopped.md)
- [Call Siprec Failed](https://developers.telnyx.com/api-reference/callbacks/call-siprec-failed.md)
- [Call Speak Started](https://developers.telnyx.com/api-reference/callbacks/call-speak-started.md)
- [Transcription](https://developers.telnyx.com/api-reference/callbacks/transcription.md)
- [Call Machine Detection Ended](https://developers.telnyx.com/api-reference/callbacks/call-machine-detection-ended.md)
- [Call Machine Greeting Ended](https://developers.telnyx.com/api-reference/callbacks/call-machine-greeting-ended.md)
- [Call Machine Premium Detection Ended](https://developers.telnyx.com/api-reference/callbacks/call-machine-premium-detection-ended.md)
- [Call Machine Premium Greeting Ended](https://developers.telnyx.com/api-reference/callbacks/call-machine-premium-greeting-ended.md)
- [Conference Created](https://developers.telnyx.com/api-reference/callbacks/conference-created.md)
- [Conference Ended](https://developers.telnyx.com/api-reference/callbacks/conference-ended.md)
- [Conference Floor Changed](https://developers.telnyx.com/api-reference/callbacks/conference-floor-changed.md)
- [Conference Participant Joined](https://developers.telnyx.com/api-reference/callbacks/conference-participant-joined.md)
- [Conference Participant Left](https://developers.telnyx.com/api-reference/callbacks/conference-participant-left.md)
- [Conference Participant Playback Ended](https://developers.telnyx.com/api-reference/callbacks/conference-participant-playback-ended.md)
- [Conference Participant Playback Started](https://developers.telnyx.com/api-reference/callbacks/conference-participant-playback-started.md)
- [Conference Participant Speak Ended](https://developers.telnyx.com/api-reference/callbacks/conference-participant-speak-ended.md)
- [Conference Participant Speak Started](https://developers.telnyx.com/api-reference/callbacks/conference-participant-speak-started.md)
- [Conference Playback Ended](https://developers.telnyx.com/api-reference/callbacks/conference-playback-ended.md)
- [Conference Playback Started](https://developers.telnyx.com/api-reference/callbacks/conference-playback-started.md)
- [Conference Recording Saved](https://developers.telnyx.com/api-reference/callbacks/conference-recording-saved.md)
- [Conference Speak Ended](https://developers.telnyx.com/api-reference/callbacks/conference-speak-ended.md)
- [Conference Speak Started](https://developers.telnyx.com/api-reference/callbacks/conference-speak-started.md)

### Conference Commands

- [List conferences](https://developers.telnyx.com/api-reference/conference-commands/list-conferences.md): Lists conferences. Conferences are created on demand, and will expire after all participants have left the conference or after 4 hours regardless of the number…
- [Create conference](https://developers.telnyx.com/api-reference/conference-commands/create-conference.md): Create a conference from an existing call leg using a `call_control_id` and a conference name. Upon creating the conference, the call will be automatically bri…
- [Retrieve a conference](https://developers.telnyx.com/api-reference/conference-commands/retrieve-a-conference.md): Retrieve an existing conference
- [Hold conference participants](https://developers.telnyx.com/api-reference/conference-commands/hold-conference-participants.md): Hold a list of participants in a conference call
- [Join a conference](https://developers.telnyx.com/api-reference/conference-commands/join-a-conference.md): Join an existing call leg to a conference. Issue the Join Conference command with the conference ID in the path and the `call_control_id` of the leg you wish t…
- [Leave a conference](https://developers.telnyx.com/api-reference/conference-commands/leave-a-conference.md): Removes a call leg from a conference and moves it back to parked state.
- [Mute conference participants](https://developers.telnyx.com/api-reference/conference-commands/mute-conference-participants.md): Mute a list of participants in a conference call
- [Play audio to conference participants](https://developers.telnyx.com/api-reference/conference-commands/play-audio-to-conference-participants.md): Play audio to all or some participants on a conference call.
- [Conference recording pause](https://developers.telnyx.com/api-reference/conference-commands/conference-recording-pause.md): Pause conference recording.
- [Conference recording resume](https://developers.telnyx.com/api-reference/conference-commands/conference-recording-resume.md): Resume conference recording.
- [Conference recording start](https://developers.telnyx.com/api-reference/conference-commands/conference-recording-start.md): Start recording the conference. Recording will stop on conference end, or via the Stop Recording command.
- [Conference recording stop](https://developers.telnyx.com/api-reference/conference-commands/conference-recording-stop.md): Stop recording the conference.
- [Speak text to conference participants](https://developers.telnyx.com/api-reference/conference-commands/speak-text-to-conference-participants.md): Convert text to speech and play it to all or some participants.
- [Stop audio being played on the conference](https://developers.telnyx.com/api-reference/conference-commands/stop-audio-being-played-on-the-conference.md): Stop audio being played to all or some participants on a conference call.
- [Unhold conference participants](https://developers.telnyx.com/api-reference/conference-commands/unhold-conference-participants.md): Unhold a list of participants in a conference call
- [Unmute conference participants](https://developers.telnyx.com/api-reference/conference-commands/unmute-conference-participants.md): Unmute a list of participants in a conference call
- [Update conference participant](https://developers.telnyx.com/api-reference/conference-commands/update-conference-participant.md): Update conference participant supervisor_role
- [End a conference](https://developers.telnyx.com/api-reference/conference-commands/end-a-conference.md): End a conference and terminate all active participants.
- [Gather DTMF using audio prompt in a conference](https://developers.telnyx.com/api-reference/conference-commands/gather-dtmf-using-audio-prompt-in-a-conference.md): Play an audio file to a specific conference participant and gather DTMF input.
- [Send DTMF to conference participants](https://developers.telnyx.com/api-reference/conference-commands/send-dtmf-to-conference-participants.md): Send DTMF tones to one or more conference participants.
- [List conference participants](https://developers.telnyx.com/api-reference/conference-commands/list-conference-participants.md): Lists conference participants
- [Retrieve a conference participant](https://developers.telnyx.com/api-reference/conference-commands/retrieve-a-conference-participant.md): Retrieve details of a specific conference participant by their ID or label.
- [Update a conference participant](https://developers.telnyx.com/api-reference/conference-commands/update-a-conference-participant.md): Update properties of a conference participant.